James malcolm



UNITED STATES PATENT OFFICE.

JAMES MALCOLM, OF NEW YORK, N. Y.

IMPROVEMENT IN THE MANUFACTURE OF COLORED VULCANIZED INDIA-RUBBER ANDGUTTA-PERCHA COMPOUNDS.

Specification forming part of Letters Patent No. 51, 849, dated January2, 1866.

To all whom it may concern:

Be it known that I, JAMES MALCOLM, of New York, in the county and Stateof New York, have invented certain new and useful Improvements in theManufacture of Colored Vulcanized India -Rubber or Gutta-PerchaCompounds; and I hereby declare that the following is afull, clear, andexact description of the same.

Colored vulcanized iudia-rubber or guttapercha compounds, as produced bythe method heretofore known or practiced, was either had in color or toobrittle to become fit for practical uses, or when prepared as a compoundfor subsequent vulcanization both the color and rubber were deterioratedby action of heat.

The object of my invention, therefore, is the production of coloredrubber by incorporating in the vulcanizable compound ingredientsprepared in such amanner as that when submitted to the ordinary processof vulcanization and to the process of developing color the vulcanizedrubber or gum obtained, whether soft or hard, will be of a permanentcolor, of the desired tint or shade.

To enable others to make and use my inven tion, I shall now proceed todescribe the manner in which the same is or may be carried into effect.

The rubber, gutta-percha, or other vulcanizable gum is prepared forvulcanization in the manner well known to rubber manufacturers bycombining it with sulphur. \Vith the rubber compound I use a pigment orcoloringmatter or base for the coloring-matter which is the sulphuret ofzinc. There are two ways of preparing this substance-i. 6., byprecipitation and by fusion. The sulphuret of zinc obtained by thelatterprocess produces a brittle compound. I therefore prefer to use the oneobtained by heating metallic zinc in presence of flower of sulphur, orby igniting the dry oxide of zinc in the sulphur. The sulphuret of zincthus obtained is placed in a retort heated to white heat. This, too, Ideem essential to my improvement. When the sulphuret of zinc is preparedin the manner described it is sifted to a fine impalpable powder, andmay then be incorporated with the vulcanized rubber or gutta-perchacompound. The object of thus treating the rubber is to give it a whitishor cream color without rendering it brittle, as is the case when thewhite oxide of zinc is mixed with the compound.

If it is desired to give the rubber a red or reddish color or hue,vermillion or other suitable coloring-matter may be mixed with thesulphuret of zinc in various proportions. Other coloring ingredients maybe mixed to produce different effects of color and tint.

The compound thus prepared may be run into plastic sheets, and sold assuch to be fashioned into various articles previous to vulcanization.For dental purposes, for instance, the sheets may be formed into platesfor the reception of artificial teeth and vulcanized. Aftervulcanization, the article, if it be hard rubber, is polished andexposed to solar rays for a few hours, more or less. By immersing thevulcanized compound in alcohol while exposed to solar rays, the color ismore perfectly developed. By thus proceeding the intended color will bedeveloped.

The rubber compound in which the pigment described is used is preparedin the usual manner with reference to the intended degree of hardness orelasticity.

Vulcanized rubber may thus be produced colored or tinted, and possessingvarious degrees of hardness, by changing the proportions of theingredients named, or by mixing therewith other ingredients.

Having thus described my said invention, and the manner in which thesame is or may be carried into efl'ect, I claim- 1. The plastic compoundherein described, the same consisting of india-rubber or othervulcanizable gum, sulphur, and a pigment prepared as herein set forth,and this is claimed whether the said composition contains otheringredients or not.

2. As a new manufacture, colored vulcanized gum when composed ofindie-rubber or other vulcaniza-ble gums, sulphur, and a pigment such asherein described, and, when incorporated, subjected to vulcanizing-heat,and this is claimed whether the said compound contains other ingredientsor not.

In testimony whereof I have signed my name to this specification beforetwo subscribing witnesses.

New York, October 18, 1865.

JAMES MALCOLM.

Witnesses:

A. PoLLoK, D. B. DUDLEY.

